Jimmy Fallon burst into song and news vet Tom Brokaw got to chat up TV beauties Julianna Margulies and Stephanie March. It was Jury Appreciation Day in Manhattan Supreme Court, the annual salute to jurors featuring celebs who have been called to duty this year. Yesterday’s guests also included (back row) Julia Stiles, America Ferrera, Ralph Lauren and Elisabeth Hasselbeck. Fallon quipped, “You sit at home in your apartment, and you watch ‘Law & Order,’ and you want to do this kind of stuff.”